That is a good method, however, I have a GUI approach to this.
1.) Download the latest flash file (of course)
2.) As root, open Thunar and locate the downloaded file
3.) right click on that file and select to open with xarchiver
4.) Select the libflashplayer.so file so that it is highlighted, and select to extract selected files
5.) browse to /usr/lib/mozilla/plugins/ to use as the extraction point
6.) make sure to select option to "overwrite existing..." and extract
7.) close xarchiver and Thunar, you are done